Biomedical subjects

Yasuhiro Morisaki

Publications and source records attributed to Yasuhiro Morisaki.

5 recordsLinked to original sources

PubMed2006

Through-space conjugated polymers based on cyclophanes.

Conjugated polymers display unique electronic and optical properties, which favor their use in applications as optoelectronic materials and molecular devices. Despite the recent remarkable progress in the chemistry of conjugated polymers, the synthesis of conjugated polymers containing cyclophane units in the main chain is limited to only a few examples. This Minireview presents recent developments in the synthesis, properties, and applications of through-space conjugated polymers based on cyclophanes.

Journal Article↗

PubMed2006

Synthesis and characterization of Dithia[3.3](2,6)pyridinophane-containing polymers: application to the palladium-catalyzed Heck reaction.

[reaction: see text] We synthesized zigzag polymers consisting of dithia[3.3](2,6)pyridinophane units that were flipped rapidly as a result of syn-[anti]-syn isomerization. Pyridinophane units were fixed in the syn form by complexation with palladium, and the resulting polymer complex exhibited a high catalytic activity for the Heck coupling reaction.

Journal Article↗

PubMed2006

A one-pot synthesis and functionalization of polyynes.

[reaction: see text] A one-pot synthesis and derivatization of diynes and triynes is reported. The polyyne framework is formed from a dibromoolefin precursor based on a carbenoid rearrangement, and the resulting Li-acetylide is then trapped in situ with an electrophile to provide functionalized di- and triynes. Alternatively, transmetalation of the Li-acetylide intermediate provides either the Zn- or Sn-acetylide, which then allows for the divergent preparation of diaryl polyynes or aryl ynones via palladium-catalyzed cross-coupling reactions.

Journal Article↗

PubMed2002

Ruthenium-catalyzed s-propargylation of thiols enables the rapid synthesis of propargylic sulfides.

A new and highly efficient catalytic system based on CpRuClL2 is proposed for the S-propargylation of thiols by propargylic carbonates under neutral conditions, in which specific requirements inherent to the different reactivities of aliphatic and aromatic thiols are achieved by tuning both the nature of the ancillary ligand L and the experimental conditions.

Alkynes↗

PubMed1996

Ruthenium Complex-Controlled Catalytic N-Mono- or N,N-Dialkylation of Heteroaromatic Amines with Alcohols.

Heteroaromatic amines were N-alkylated with primary alcohols at 150-200 degrees C in the presence of a catalytic amount of various ruthenium complexes to give the corresponding monoalkylated and dialkylated amines in good to high yields. For example, 2-aminopyridine reacted with an excess of ethanol at 180 degrees C for 20 h in the presence of dichlorotris(triphenylphosphine)ruthenium [RuCl(2)(PPh(3))(3)] to give 2-(ethylamino)pyridine (1) and 2-(diethylamino)pyridine (2) in 9% and 70% yields, respectively. On the other hand, when (eta(4)-1,5-cyclooctadiene)(eta(6)-1,3,5-cyclooctatriene)ruthenium [Ru(cod)(cot)] was used as a catalyst, even in the presence of excess ethanol, 1 was obtained in 85% yield with high selectivity. The addition of tertiary phosphines and phosphites to Ru(cod)(cot) increased the yield of the dialkylated amine.

Journal Article↗